Suspended refractory construction



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SUSPENDED REFRACTORY CONSTRUCTION Filed Jun; 9, 1965 5 Sheets-Sheet 5 INVEN 0R5 me i L. J 652% ATTO R N EYS United States Patent SUSPENDED REFRACTbRY CONSTRUCTION Joseph L. Stein, Cherry Hill, N.J., and Milton H. Koeneman, Paoli, Pa., assignors to General Refractories Company, Philadelphia, Pa., a corporation of Pennsylvania Filed June 9, 1965, Ser. No. 462,643 6 Claims. (Cl. 110-99) The present invention relates to a suspended refractory roof and particularly to a continuously interlocked refractory roof. which is suspended at intermittent positions in the roof structure.

A purpose of the invention is to provide a strong, sound, economically feasible, basic refractory roof.

A further purpose is to minimize the amount of superstructure, beams and suspension members necessary in a refractory roof construction while making use of existing hold-down beams which are very prevalent in existing furnace construction.

A further purpose is to utilize the structural characteristics of the refractory brick to provide a continuous roof interlock.

A further purpose is to prevent loss of spalled bricks by means of interlocking the bricks.

A further purpose is to maintain the roof in proper displacement and fixed contour, particularly during periods of varying temperature exposures, such as furnace shut-downs.

A further purpose is to allow localized individual portions of the roof to be removed and replaced without interfering with the roof and suspension at other locations.

A further purpose is to provide a basic refractory roof which will have a longer life and which can be exposed to more heats.

A further purpose is to utilize an interlocking brick construction in a semi-suspended roof.

A further purpose is to utilize an interlocking construction to avoid dropout of spalled portions of the roof.

A further purpose is to interlock each brick in a roof construction from a minimum number of individually suspended bricks.

A further purpose is to eliminate the use of individual separate structural members in the form of steel plates on or between brick rings in a suspended roof construction.

A further purpose is to eliminate the need for transverse plate hold-down beams in a suspended roof construction.

A further purpose is to allow the bricks to be placed in an inverted relationship where necessary.

A further purpose is to remove some of the thrust load imparted to the arch bricks in prior art refractory roof construction, particularly during heat-ups subsequent to roof installation.

A further purpose of the invention is to hold every brick in the roof up and also to hold it down, either by a direct suspension, or by an interlocking arrangement with the fixed bricks, by having every brick held rigidly in place in a basic refractory roof, the entirestructure being protected against failure by weakening and buckling, especially when the roof begins to wear thin.

A further purpose is to prevent upward or downward movement of the roof between the hold-down beams by use of interlocking X-shaped brick.

A further purpose is to eliminate heavy transverse stiffening plates extending over and between brick rows in sprung or suspended roofs.

A further purpose of the invention is to assemble a basic refractory roof which will give better service under the existing conditions of an open-hearth steel-making furnace or other similar high temperature furnaces.

A further purpose is to permit more rapid assembly of a basic refractory roof.

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A further purpose is to obtain longer life from a basic refractory roof.

Further purposes appear in the specifications and in the claims.

In the drawings we have chosen to illustrate a few only of the numerous embodiments in which our invention may appear, selecting the forms shown from the standpoin-ts of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a diagrammatic vertical transverse section of a suspended arch in accordance with the invention.

FIGURE 2 is a fragmentary enlarged elevational section of the lower end of the suspension member at its point of connection to the transverse longitudinal beam.

FIGURE 3 is a fragmentary enlarged perspective of a portion of the arch shown in FIGURE 1 showing the suspension and brick connection.

FIGURE 4 is a perspective view of an individual brick in the arch of FIGURE 1.

FIGURE 5 is a perspective view of a metal plate prior to bending and prior to the attachment to the brick in FIGURE 4.

FIGURE 6 is a fragmentary end perspective of the brick of the arch of FIGURE 1 showing a tab extending from the cold end of the brick.

FIGURE 7 is a perspective view of an oxidizable metallic plate with a hanger tab attached thereto.

I FIGURE 8 is a top plan view of an individual brick of the arch shown in FIGURE 1.

FIGURE 9 is a front elevation of the brick of FIG- URE 8. 1

FIGURE 10 is a side elevation of the brick of FIG- URE 9.

FIGURE 11 is an end elevation showing means for attaching individual bricks to a longitudinal beam in a super-structure.

FIGURE 12 is a fragmentary enlarged perspective view of the end of the brick rows showing the adaptation of the construction of the invention to a standard skew face.

FIGURE 13 is a fragmentary enlarged perspective view of a mid-section of the arch of'the invention showing the staggered use of key-out shapes for roof ring construction.

Prior art furnace roofs have been essentially of the sprung arch type and of the suspended roof type.

For many years, open-hearth steel furnaces and other metallurgical furnaces had been provided with sprung arch roofs of acid brick. Such acid brick were ordinarily made of silica and had the advantage of production at low cost and of possessing the physical properties, particularly high crushing strength and spalling resistance at operating temperature which permitted their use in sprung arches.

Metallurgical requirements changed so that non-acid, or basic, bricks became desirable.

Early efforts to use such basic refractory bricks in sprung arches were unsuccessful because of the low crushing strength of the non-acid bricks at furnace operating temperatures and the tendency of arches of non-acid bricks to fail through shearing and spalling.

Additional failure occurred due to uneven wear and loss of arch contour.

To permit use of basic refractory brick, a superstructure of steel framing was extended over the refractory roof, and individual basic bricks in the roof were sus-' pended and supported from the superstructure. This suspension system took various forms, but generally included anchored jacks supporting longitudinal beams positioned lengthwise of the furnace and in contact with the upper surface of the refractory roof. These lengthwise extending beams were spaced circumferentially along the arc of the arch, and, for instance, were seven in number.

Various intricate suspension arrangements extended from these longitudinal beams in an effort to structurally secure and support each and every individual brick from the superstructure.

In some instances, these intricate suspension systems took the form of steel girder plates extending between rows of brick in a direction transverse to the roof. The bricks reacted with the plate to form a bond between brick and plate.

In other instances, each brick of the roof was individually suspended from the girder plate extending between the rows of brick. Such an arrangement is shown in U.S. Patent 3,005,424. In other instances the girder plates were placed over the brick, and the bricks individually suspended by means of individual hangers. This is shown in U.S. Patent 3,093,099.

Disadvantages of such intricate suspension systems included large initial expense of installation, complex maintenance, and poor roof accessibility.

In the present invention, the intricate suspension systems of the prior art are eliminated. The roof of the present invention utilizes the lengthwise or longitudinal beams to support and secure certain bricks in the roof and these certain bricks in turn are interlocked with the remaining bricks in the roof. This interlock is provided by a special shape refractory brick which provides resistance against any of the bricks moving radially outward of the arch, or moving radially inward of the arch. These bricks are generally of an X-shape cross section when viewed in a transverse vertical plane when the brick is in the roof.

Considering the arch shown in FIGURE 1, we illustrate a furnace 20, suitably an open-hearth, having a front wall 21, a back wall 22 and an arch roof 23 which runs lengthwise of the furnace. At the front end is'a beam 24 which supports thereon a front skewback 25 and at the rear end is a beam 26 which supports rear skewback 27. These skewbacks run the full length of the furnace and at least partially support the arch brick.

Beams 30 run longitudinally of the arch and are in contact with the arch.

Suitably supported at the front and back of the furnace is an overhead steel supporting structure 31 which is connected to the beams by jacks 32 suitably consisting of pipes or other struts which at the lower end are bolted, or pinned at 33 to angles 34 which are riveted, bolted or welded at 35 to beams 30, and which at the upper end extend through tubular connectors 36 secured to the supporting structure, and are locked in place by pin 37. It will be noted that the longitudinal beams 30 are spaced radially over the arch.

Between the skewbacks extend a series of rows of arch brick 40, which are desirably of the character shown in FIGURES 3, 4 and 8 to 10. Each of the bricks has a refractory mass of material, for instance, chrome, magnesia, chrome-magnesite or rnagnesite-chrome, of a suitable character.

The brick 40 has two integral longitudinal half-sections 41 and 42. Each of the longitudinal half-sections 41 and 42 has a common cold face 43 and a common hot face 44. The half-section 41 has opposed, slightly converging radial faces 46 and 47, and the half-section 42 has opposed, slightly converging radial faces 48 and 50. The faces 46 and 47 converge to the same degree as the faces 48 and 50. The half-section 41 has a transverse face 51 and the half-section 42 has a transverse face 52.

In a typical brick of the invention, the brick is 12 inches in length, and the faces 51 and 52 are generally three inches wide at the widest point. The faces 46, 47, 48 and 50 are approximately two inches wide at the narrowest point. The longitudinal half-sections 41 and 42 form V or wedge shape surfaces 53, 55, 56 and 57, which extend between the adjoining offset radial faces and which are broadest at the hot and cold end of the brick and which taper to the apex of the V toward the middle of the brick.

The faces 47 and 50 are suitably offset /2 inch with respect to one another at the cold face 43 and at the hot face 44, and the faces 46 and 48 are likewise suitably offset /2 inch with respect to one another at the hot and cold faces respectively.

The wedge shape surfaces 53, 55, 56 and 57 are preferably obliquely inclined to the transverse planes of the brick lying parallel to the transverse faces 51 and 52.

The brick 40 in side elevation as seen in FIGURE 10, is in the form of an X. The longitudinal half-sections 41 and 42 respectively form the arms of the X.

Additionally, the sides 46 and 50 are slightly smaller in width, for instance A inch smaller, than the sides 47 and 48 to avoid interference when the bricks are interlocked in the roof.

Preferably co-molded with the refractory is an oxidizable metallic plate 60 which is formed from a flat plate as shown in FIGURE 5. The plate has horizontal, parallel sides 61 and 62, parallel ends 63 and 65 and V- shaped notches 66 and 67 which extend generally longitudinally in the center of the plate. The V-shaped notch 66 has a tapered side 68 and a tapered side 70. The V-shaped notch 67 has a tapered side 71 and a tapered side 72. The notches 66 and 67 may have stress relief fillets 72 and 72 at the apex of the Vs to eliminate high stress concentration which could result in plate failure when the plate is bent. The plate has lanced tongues 73 which are perforated from the plate and extend into the refractory of the brick when the plate is co-molded with the brick. The plate is pre-bent in an offset manner so that the plate conforms to the brick surface as is best seen in FIGURE 3. The plate is co-molded to the refractory of the brick in a press having die shapes which yield a brick as described above.

A tab 75 extends integrally from one of the plates of selected brick as shown in FIGURE 6. It should be understood that more than one tab may extend from an individual brick. Said tab can lie against the cold face 43 of the brick when the brick is stored or in transit. The tab can then be bent outwardly of the cold face 43 so that the web portion 76 extends transversely of the cold end of the brick when the brick is put into service. An offset portion 77 has a suitable hole at 78 which engages a hanger extending over beam 30 as will later be explained.

An alternate form of hanger arrangement is shown in FIGURE 7 where a separate hanger tab 80 is formed into a web portion 81, an outwardly directed portion 82 and a diagonal portion 83. A hanger portion 84 extends from the web portion 81 and initially extends along the cold end of the brick while the brick is manufactured, stored and transported. The web portion 81 is suitably secured to the plate 60 by Welding or other means. When the brick is placed in operation, the hanger portion 84 is bent through a right angle so that the hole 85 can engage a hanger extending over the beam 30.

In FIGURE 3, an alternative form of hanger 86 which can be integral with the plate or which can be comolded with the refractory and attached to the plate as shown in FIGURE 7 has a tab portion 87 which is offset from the longitudinal half-section with which it is associated. The portion 87 is normally bent so that the hanger extension is along the cold face of the brick and when the brick is placed in operation the hanger is bent upward to lie in the longitudinal plane of the brick as seen in FIGURE 3. The hole 88 in the tab 86 is placed over the center of the brick so that in the roof assembly, opposing tabs of adjacent bricks can be matched whereby the holes 88 will align in order to permit a hanger to pass therethrough.

Where tabs are placed on more than one radial face of the bricks, selected and matching tabs can be used for engaging the hanger, with the non-selected tabs remaining inactive.

The hangers are placed on selected plates only as will be readily explainedwhen the roof assembly is described.

As well known, all of the oxidizable metallic plates are relatively thin, for instance, of a 20 gauge thickness and desirably of plain carbon or low alloy steel, for instance, AISI -10 or 10-35. The oxidizable metallic plate oxidizes and reacts with the refractory as well known in the art.

Considering now the assembly of the roof of the invention, conventional skewbacks 25 as seen in FIGURES 1 and 12 having a vertical face 90, inclined face 91, and recessed portion 92, are placed on the beam 24, and supported thereon. A special adapter brick 93 having a fiat common radial side 95,-olfset radial sides 96 and 97, transverse sides 98, a cold end 101, and a hot end 102 is placed on the skewback 25 with the face 95 of the adapter back 93 abutting the face 91 of the skewback 25.

The adapter bricks have a staggered transverse depth as shown by bricks 93, 103 and 105 in FIGURE 12, so that the transverse rows of interlocking bricks 40 have staggered joints. This prevents any through planes from brick ring to adjacent brick ring.

A brick 40, as described above, is then placed in matching relationship with the adapter brick 93, so that the longitudinally offset portions 41 and 42 engage and interlock with the faces 96 and 97 of the adapter brick 93. Each succeeding brick is then placed in the transverse ring until the center of the transverse arch is approached. An adapter brick 106 similar to the brick 93 is used at the end of the transverse row at the skewback 27 opposite the skewback 25 as seen in FIGURE 1 and bricks 40 are placed into the transverse ring described above until the bricks approach the center and uppermost point on the ring.

Thus, each transverse ring of the invention is built from each of the opposing skewbacks toward the crest or uppermost point on the row. As the crest is reached, adapter bricks 110, 111, and 113 are used to complete the arch as seen in FIGURE 13. Adapter bricks 110 and 111 are in reality sections of a brick 40, radially split along a radial face 115. The bricks 110 and 111 are placed on respectively opposed arch bricks 40. A standard driving wedge taper brick 113 of a size suitable to fill the gap between the adapter bricks 110 and 111' is then driven into place to completely fix the transverse row of the arch, as shown in FIGURE 13.

In many instances, it will be desirable to use a number of adapter bricks 110, 111, and 113, to key the arch more firmly at a plurality of circumferential positions in the arch, and in such instance the same procedure for keying as described above is followed. More than one such key arrangement is most desirable when larger spans are used.

In some instances, it may be desirable to use brick 40 which is not full size transversely in the ring as the remaining brick in the row, but otherwise conform in all other dimensions to the brick 40, as shown, for instance, at 116 and 117 in FIGURE 13. These small sized brick 116 and 117 are used to provide an adjustment in bricks positioned transversely in the row.

Undersized bricks 116 and 117 of varying transverse dimension in the brick ring are also used to compensate for alignment tabs in the roof construction so that the brick 40 are properly positioned with respect to the beam 30 as later described. Succeeding transverse rows of brick are placed in position longitudinally of the roof until the entire roof is covered.

The arch at this stage of construction is essentially a sprung arch with interlocking bricks in each transverse row of the arch. The interlocking of the bricks is such that each of the bricks is supported against radial inward movement of the arch by the faces 46 and 50 of the brick 40 as best seen in FIGURES 3 and 10, and each of the bricks is supported against movement radially outward of the arch by the faces 47 and 48 of brick 40.

As indicated by lines a and b of FIGURE 10 which are line extensions of thefaces 46 and 50, each of the brick 40 have a sharper taper angle than the conventional prior art taper brick.

The beams 30 are placed in position and are adjusted by means of the jacks'32 so that each beam comes into firm contact with the top of the arch as shown generally in FIGURE 1, and in enlarged detail n FIGURES 3 and 11. The beam 30 acts as a hold-down member against the two adjacent bricks 117 and 118 directly below the beam. Additionally, the beam 30 acts as a hold-up mem her for bricks 118, 119, 120 and 121 which have afiixed thereto hanger tabs 86. A hanger 122, suitably in the form of a wire or rod, extends over the beam30, down along the sides of the beam at 123, and is then hooked through the hanger tabs 124. There is shown in FIGURE 11 a convenient way of sliding the hanger tabs 86 over the hanger while it extends horizontally as at 125. The hanger is then bent up vertically as shown at 126. It will be noted that the hangers are positioned on the bricks at appropriate longitudinally olfset portions of the brick, so that the hanger 122 can pass through preferably four hanger tabs. Adjuster bricks 116 and 117 as described above are used to achieve a symmetrical position of bricks 118, 119, 120, and 121 beneath the beam 30.

In view of our invention and disclosure variations and modifications to meet individual whims or particular needs will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we, therefore, claim all such insofar as they fall within the reasonable. spirit and scope of our claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a refractory arch: spaced skewbacks; refractory brick extending between said skewbacks in transverse rows in arch form and supported at least partially on the skewbacks; an overhead supporting structure; beams supported from said overhead supporting structure and extending above said arch form rows in a longitudinal direction which is transverse to the rows of bricks; said beams being suspended in parallel relationship and spaced radially from one another adjacent to and in contact with the cold face of the brick arch; said transverse 'rows including interlocking refractory brick, each of said interlocking refractory brick having integral half-sections displaced with respect to each other longitudinally of the arch; said half-sections including a first half-section having two opposed radial faces slightly converging toward one another in a first direction, and a second half-section having two opposed radial faces slightly converging toward one another in a second direction displaced from said first direction, the half-sections forming a generally X-shape wherein the first half-section forms one arm of the X and the second half-section forms the other arm of the X; some of said interlocking brick adjacent said beam having first hangers extending from the brick; and hanger means extending from the beams and in engagement with the first hanger means on the brick; wherein said interlocking refractory brick in said transverse rows includes first brick in fixed hold-down and hold-up relationship with said beams, and second brick interlocked with said first brick and held in a hold-down and hold-up relationship in the arch from the first brick.

2. A refractory arch of claim 1 wherein the transverse rows include at their ends adapter bricks having a flat face inclined to the horizontal and in contact with the spaced skewbacks.

3. A refractory arch of claim 1 wherein the first hangers have offset tabs wherein the tab is attached to the brick at a point displaced horizontally from the center of gravity of the brick, and is attached to the beam hanger means at a point above the center of gravity of the brick.

4. A refractory arch of claim 1 wherein the brick 7 have on their surface co-molded oxidizable metallic plates.

5. A refractory arch of claim 1 wherein each of the transverse rows include interlocking adjuster bricks varying in depth along the direction of the transverse row wherein the interlocking refractory brick are symmetrically positioned below the beams.

6. A refractory arch of claim 1 wherein each of the transverse rows have key bricks including split interlocking bricks and wedge shape taper bricks.

References Cited UNITED STATES PATENTS 855,495 6/1907 Baldwin 110-99 8. Reintjes- 110-99 X Longenecker 110.99

Heuer 110 -99 Grigsby 110-99 Murray 110-99 Stein 110-99 EDGAR W. GEOGHEGAN, Primary Examiner.

ROBERT A. DUA, Examiner. 

1. IN A REFRACTORY ARCH: SPACED SHEWBACKS; REFRACTORY BRICK EXTENDING BETWEEN SAID SKEWBACKS IN TRANSVERSE ROWS IN ARCH FORM AND SUPPORTED AT LEAST PARTIALLY ON THE SKEWBACKS; AN OVERHEAD SUPPORTING STRUCTURE; BEAMS SUPPORTED FROM SAID OVERHEAD SUPPORTING STRUCTURE AND EXTENDING ABOVE SAID ARCH FORM ROWS IN A LONGITUDINAL DIRECTION WHICH IS TRANSVERSE TO THE ROWS OF BRICKS; SAID BEAMS BEING SUSPENDED IN PARALLEL RELATIONSHIP AND SPACED RADIALLY FROM ONE ANOTHER ADJACENT TO AND IN CONTACT WITH THE COLD FACE OF THE BRICK ARCH; SAID TRANSVERSE ROWS INCLUDING INTERLOCKING REFRACTORY BRICK, EACH OF SAID INTERLOCKING REFRACTORY BRICK HAVING INTEGRAL HALF-SECTIONS DISPLACED WITH RESPECT TO EACH OTHER LONGITUDINALLY OF THE ARCH; SAID HALF-SECTIONS INCLUDING A FIRST HALF-SECTION HAVING TWO OPPOSED RADIAL FACES SLIGHTLY CONVERGING TOWARD ONE ANOTHER IN A FIRST DIRECTION, AND A SECOND HALF-SECTION HAVING TWO OPPOSED RADIAL FACES SLIGHTLY CONVERGING TOWARD ONE ANOTHER IN A SECOND DIRECTION DISPLACED FROM SAID FIRST DIRECTION, THE HALF-SECTION FORMING A GENERALLY X-SHAPE WHEREIN THE FIRST HALF-SECTIONS FORMS ONE ARM OF THE X AND THE SECOND HALF-SECTION FORMS THE OTHER ARM OF THE X; SOME OF SAID INTERLOCKING BRICK ADJACENT SAID BEAM HAVING FIRST HANGERS EXTENDING FROM THE BRICK; AND HANGER MEANS EXTENDING FROM THE BEAMS AND IN ENGAGEMENT WITH THE FIRST HANGER MEANS ON THE BRICK; WHEREIN SAID INTERLOCKING REFRACTORY BRICK IN SAID TRANSVERSE ROWS INCLUDES FIRST BRICK IN FIXED HOLD-DOWN AND HOLD-UP RELATIONSHIP WITH SAID BEAMS, AND SECOND BRICK INTERLOCKED RELATIONSHIP IN THE ARCH FROM THE FIRST BRICK. 